40,653 research outputs found

    Survival and Food Detection by First-Instar \u3ci\u3eMelanoplus Femurrubrum\u3c/i\u3e (Orthoptera: Acrididae)

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    Newly hatched Melanoplus femurrubrum (DeGeer) were evaluated for survival without food under various moisture, temperature, and light conditions. Although nymphs survived up to 113 h without food, they required food 48-W h after hatching to ensure continued survival and growth. Olfactory food detection was very limited and feeding tended to occur on the first suitable food encountered. Food covered with a ftlm of water and held within several millimetres of the palpi evoked palpal vibrations followed by antennal movements. The evidence suggests that hygroreceptors occur on the pa\pi and pa\pa\ stimulation is necessary before antennal olfaction occurs

    New Orthopteroid Records in Michigan Derived from Sampling a Small Field

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    (excerpt) A 1.8 acre sandy field in Isabella County, Michigan was sampled in 1971 and 1972 to obtain data on ecological and chronological distribution of orthopteroid species (Bland and Swayze 1973a,b). The upland field vegetation was a mosaic of numerous non- contiguous floral associations (e.g. moss-grass, grass-milkweed, goldenrod-bergamot-fern) made up of 58 plant species. The land, bordered by shrubs, trees and a road, was relatively isolated. Sampling was done both day and night once a week by using sweep nets and 7 to 21 pit traps (some containing molasses as bait)

    Antennal and Mouthpart Sensilla of the Blister Beetle. \u3ci\u3eMeloe Campanicollis\u3c/i\u3e (Coleoptera: Meloidae)

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    Sensilia on the sexually dimorphic antennae of the blister beetle, Meloe campanicollis, were primarily sensilla chaetica with scattered socketed and non-socketed sensilla basiconica. Forked chaetifonn sensilla on the female\u27s first segment are displaced by the antennal socket rim when the male grasps and lifts her antennae with segments 5 to 7 of his antennae. Segments 5 to 7 lack dense sensilla chaetica and have only patches of shorter sensilla. The segments also contain a high density of epidennal gland ducts compared to other segments. Maxillary palpi apices were similar in males and females, but the female\u27s labial palpi contained fewer narrow and many more short, broad sensilla basiconica than the male·s

    The 5-D Choptuik critical exponent and holography

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    Recently, a holographic argument was used to relate the saturation exponent, γBFKL\gamma_{BFKL}, of four-dimensional Yang-Mills theory in the Regge limit to the Choptuik critical scaling exponent, γ5d\gamma_{5d}, in 5-dimensional black hole formation via scalar field collapse \cite{alvarez-gaume}. Remarkably, the numerical value of the former agreed quite well with previous calculations of the latter. We present new results of an improved calculation of γ5d\gamma_{5d} with substantially decreased numerical error. Our current result is γ5d=0.4131±0.0001\gamma_{5d} = 0.4131 \pm 0.0001, which is close to, but not in strict agreement with, the value of γBFKL=0.409552\gamma_{BFKL}=0.409552 quoted in \cite{alvarez-gaume}.Comment: 11 pagers, 2 figure

    Measuring Outer Disk Warps with Optical Spectroscopy

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    Warps in the outer gaseous disks of galaxies are a ubiquitous phenomenon, but it is unclear what generates them. One theory is that warps are generated internally through spontaneous bending instabilities. Other theories suggest that they result from the interaction of the outer disk with accreting extragalactic material. In this case, we expect to find cases where the circular velocity of the warp gas is poorly correlated with the rotational velocity of the galaxy disk at the same radius. Optical spectroscopy presents itself as an interesting alternative to 21-cm observations for testing this prediction, because (i) separating the kinematics of the warp from those of the disk requires a spatial resolution that is higher than what is achieved at 21 cm at low HI column density; (ii) optical spectroscopy also provides important information on star formation rates, gas excitation, and chemical abundances, which provide clues to the origin of the gas in warps. We present here preliminary results of a study of the kinematics of gas in the outer-disk warps of seven edge-on galaxies, using multi-hour VLT/FORS2 spectroscopy.Comment: 7 pages, 7 figures; to appear in the proceedings of IAU Symposium 254 "The Galaxy disk in a cosmological context", Copenhagen, June 200

    Stellar populations -- the next ten years

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    The study of stellar populations is a discipline that is highly dependent on both imaging and spectroscopy. I discuss techniques in different regimes of resolving power: broadband imaging (R~4), intermediate band imaging (R~16, 64), narrowband spectral imaging (R~256, 1024, 4096). In recent years, we have seen major advances in broadband all-sky surveys that are set to continue across optical and IR bands, with the added benefit of the time domain, higher sensitivity, and improved photometric accuracy. Tunable filters and integral field spectrographs are poised to make further inroads into intermediate and narrowband imaging studies of stellar populations. Further advances will come from AO-assisted imaging and imaging spectroscopy, although photometric accuracy will be challenging. Integral field spectroscopy will continue to have a major impact on future stellar population studies, extending into the near infrared once the OH suppression problem is finally resolved. A sky rendered dark will allow a host of new ideas to be explored, and old ideas to be revisited.Comment: Invited review, IAUS 241, "Stellar Populations as Building Blocks of Galaxies," eds. Vazdekis, Peletier. 12 pages, 1 table. (The sideways table should print ok; there are 10 columns.
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